Generally, a slide rail assembly includes a first rail and a second rail displaceable with respect to the first rail. When the second rail reaches a predetermined position after displacement with respect to the first rail in a particular direction, there is typically a blocking structure between the second rail and the first rail to prevent the second rail from further displacement with respect to the first rail in that particular direction, thereby keeping the second rail at the predetermined position. With the advancement of technology, a similar product has emerged in which not only can a second rail be kept at a predetermined position with respect to a first rail by a blocking mechanism, but also the blocking mechanism can be deactivated by an operating member to allow further displacement of the second rail with respect to the first rail in a certain direction. U.S. Pat. No. 6,412,891 B1, for example, discloses a slide rail assembly that includes an outer member (20), an inner member (30), a stop member (50), and a pivot member (70), wherein the pivot member (70) is pivotally connected to the inner member (30) such that, when the inner member (30) is at a predetermined position with respect to the outer member (20), the stop member (50) blocks the pivot member (70) and thereby prevents the inner member (30) from inadvertent displacement with respect to the outer member (20).
As market demands vary, however, it has been an important issue in the related industries to devise a different slide rail product by furnishing a slide rail assembly with an at least two-stage locking mechanism.